India, Feb. 24 -- Pope Francis continued to be in a critical condition on Sunday as his blood tests showed early kidney failure, the Vatican said. However, the 88-year-old pontiff remained alert, responsive and even attended Mass.

The Pope has been battling respiratory issues, including pneumonia and another complex lung infection.

The Vatican shared a health update late on Sunday and said that Francis did not suffer any more respiratory crises since Saturday night but, was still receiving major flows of supplementary oxygen, a report from The Associated Press said.

Though some blood tests showed "initial, mild, kidney failure", the doctors said that it was under control. "The complexity of the clinical picture, and the necessary wait ...